Studies over the last two decades have described the epidemiology of TBI in children and adolescents, outlined the natural history of recovery, and determined the functional outcome following injury. Important questions remain about the effect of treatment during the acute, short-term, and longer-term phases of care on the functional, psychosocial, and disability outcomes after TBI. In this project, Harborview Medical Center, Texas Children's Hospital, Nationwide Children's Hospital, and the Children's Hospital of Philadelphia propose a multicenter study of complicated mild, moderate, and severe TBI occurring to individual's ages 7-18 years to address these aims: Aim 1. Characterize complicated mild, moderate and severe TBI with respect to age, cause, type of injury, accompanying signs and symptoms, type and severity of medical and surgical co-morbidities, and pre-existing conditions, functional status at admission and discharge from the acute care hospital; and examine the association between specific characteristics of TBI and educational, vocational, behavioral, and social outcomes 6, 12, 24 and 36 months after injury. Aim 2. Determine the treatment received during the initial hospitalization for TBI, and during inpatient and outpatient rehabilitation and therapy, and the relationship of treatment to demographic and injury factors. Aim 3. Determine the association of treatment received during the acute inpatient and rehabilitation phases of care with the educational, vocational, behavioral, and social functional outcomes 6, 12, 24 and 36 months after injury, including the association with attainment of educational and vocation milestones at different developmental stages. This study will address many of the unanswered questions on pediatric TBI. It is innovative in many ways. It is a multi-centered study bringing together leading expertise in the United States on pediatric TBI. It will employ the newly developed Common Data Elements for characterizing injuries and the newly developed quality of care indicators for characterizing their inpatient rehabilitation care. The study will utilize the new PROMIS outcome measures and collect data in a longitudinal fashion from both caregivers and patients using web- based technology. By applying novel statistical approaches designed to assess causal effects in observational designs, it will provide critical information on the effects of treatment at different stages of cae on functional outcomes after TBI. The study team represents a uniquely interdisciplinary group of very experienced investigators who are capable of carrying out a rigorous study to provide information to inform future research, care and policy.